用括号内所给词组的适当形式填空。

1. —Would you mind helping me to finish the work?

    —Of course not. I'll do it __________.（立刻）

2. It's snowing outside, you'd better __________（穿上）your overcoat when you go out.

3. I__________（过去常常）collect stamps, but now I am not interested in it more.

4. __________（到目前为止）our government has taken measures to protect the environment.

5. Liu Xiang __________（参加）the 2008 Beijing Olympics,

    but it's a pity that he didn't win a gold medal.